1. Field of the Invention
This invention has to do with the forming of relatively long lengths of relatively heavy gauge steel pipe. In forming such pipe, plate stock is fed into a plate bending machine which "U"'s the plate preparing it for the crimping operation. Following the U-ing operation, crimping takes place on a separate machine. Following the crimping operation, the pipe is sent onto a machine which substantially closes the crimped product, forming it into its final round shape. After being thus closed the pipe emerges from the closing press with its two edges formed rather tightly together. In such condition, however, the pipe cannot be fed into O.D. welders which require that the edges of the pipe be passed by a vertical hanger plate that supports an internal arbor approximately 1 inch thick. It is necessary, therefore, to spread apart these closed edges so as to form a permanent opening therebetween of about one and a half inches to two inches along the full length of the pipe.
2. Description of the Prior Art
A search of the United States patent art was conducted in an effort to locate that art most pertinent to the wedge pipe spreader disclosed herein. No assertion is made, however, that the most pertinent art was indeed located, although, as indicated, that was the intent of the search. This search developed the following references:
1,994,111 Rocci 2,007,996 Baker 2,219,049 McArthur 2,613,303 Babbitt 2,845,989 Ewaldson, et al. 2,857,871 Reynolds 3,075,484 Benteler 3,191,843 Tomkins 3,198,931 Klempay 3,236,083 Minderoth, Jr. et al. 3,285,490 Roper 3,329,329 Karmann 3,362,603 Bauer 3,365,144 Daub 3,397,564 Schroeder 3,431,383 Ullery, Jr., et al. 3,452,424 Morris 3,462,059 Bauer, et al. 3,633,813 Looney 3,647,131 Hayne 3,662,940 Stettler 3,684,149 Ambler 3,765,665 Work 3,770,927 Christopher
In the only known machine of the type to spread or open 40 feet long steel pipe of 0.250 to 0.750 wall thickness, spreader units employing complicated linkage arrangements are utilized. A plurality of cylinders is needed to actuate such linkage arrangement. Although none of the art appears to disclose a heavy duty pipe spreader as described herein, perhaps the following patents from those listed above are the more relevant: 3,662,940; 3,285,490; 2,857,871; 2,845,989; 2,007,996 and 3,647,131.